Modern mobile communications devices (e.g., smartphones, tablet computers, etc.) are configured to provide a wide array of functionality. For example, a mobile communications device may include components that implement a Global Navigation Satellite System (GNSS) receiver. The GNSS receiver may be used to provide, for example, a position of the mobile communications device and a velocity of the mobile communications device. Modern mobile communications devices may alternatively determine a position and/or velocity of the device using data received from motion sensors, a received WiFi signal, and/or a received cellular signal, among other sources. Mobile communications devices may also include a variety of built-in sensors that enable the monitoring of various physical phenomena on and around the device. Such sensors include motion sensors (e.g., accelerometer, gyroscope, magnetometer, etc.) and environmental sensors (e.g., barometer sensor, temperature sensor, proximity sensor, ambient light sensor, etc.), among others. Software applications that are executed within the mobile communications device process the data generated by these sensors.